Info Wanted: People seem to think black-crush & white-blow-out are bad, why?

Many people post on here saying something about black-crush or white-blow-out, but don’t explain the context of why that is bad in the context they are talking about. However, I would think, black-crush and white-blow-out are not inherently bad and mostly dependent on direction and production.

Perhaps why thinking of what black-crush and white-blow-out is wrong and my  interpretations  are below.

Black Crush - when 2 pictures of the same scene have some dark (or shadow) details replaced with black

White Blow Ou - the opposite of black crush, when 2 pictures of the same scene have details replaced with white.

For anyone who got this far, I bring this up because I see lots of posts here and else where saying this version is bad because of black-crush or white-blow-outs, and that makes no sense.

How often do we have an accurate reference on how it looked in theaters?

Also, is how something looked in theaters, say, 95% of the time the way it is supposed to look from an objective/absolute standpoint? Does such a standpoint exist without direct words from the director/production?

On top of that and on the other hand, how many times have we seen/heard directors/production say things that seemingly seem counter-intuitive or subjectively wrong in context to selling something that was "re"-done?

Also, is it reasonable or unreasonable to say that things like black-crush and white-blow-out, which seems like could be a result of simple brightness differences, could be vastly different from theater to theater, given the print, environment,  health/eyesight/memory, and contemporary environment changes for re-screenings of vintage prints?

Again, if you've gotten this far, I'm think it would be good to provide much more context for preservation ideas and requests.

Firstly, debating whether this is off-topic or on-topic is certainly off-topic, however I do question if this topic is in fact off-topic. Can anyone chime in? Or move this post?

ElectricTriangle, thank you for replying and I agree, contemporary orange/teal and contrast boosting/bleeding are both examples of something that can to a being be absolutely determined. However, *I think* there are many cases where people mention black-crush and white-blow-out as negatives, are correct that there is black-crush and/or white-blow-out, however they fail to point out why that is bad and/or fail to show how their vision of how things are supposed to look is correct.

Other times people source LD, VHS, and film cells, which also provide no basis of how something is supposed to look or how something looked.

Again, I just would like more examples and why something needs to be preserved.

There are instances where blacks are crushed and whites are blown out well beyond the heightened contrast of 35mm theatrical prints. Ghostbusters is a great example, I saw an original print and it was nowhere near the kind of blown out as the old Blu-ray. And it looked different, photochemical contrast blow-out is one thing, digital contrast blow-out is entirely different.

2 replies, both mentioning Ghostbusters. I've seen black-crush and white-blow-out mentioned in like every (exaggeration) thread. Can't someone provide more examples of this?

Here's another example: The Good The Bad and The Ugly 4K BD

Read the thread for more info. 

Are you sure?   ;-)

I will, but you got a link in case I can't find the thread?

Also, if pointing out black-crush or blown-out-whites, isn't it only valid comparison is if there is a definitive source (barring debates regarding what is definitive) or if there is another source that has overall better black-detail (for black-crush) or overall better light-detail (for blown-out-whites)? Comparing to another source that has one scene that is better but overall poorer quality (eg Ghostbusters) doesn't seem like a fair comparison and at this point it's just mixing and matching scenes for personal preference. 

In the absence of a definitive "this is how it's definitely supposed to look" source to compare it to, I would think the source that provides the most detail would be preferable. In that case, wouldn't a release that crushes blacks and/or blows out whites to the point of losing detail in those areas be undesirable?

And I'm not talking about a movie that came out two months ago with crushed blacks and blown-out whites, since that's likely a creative decision. I'm talking about a movie that's been out for years in many different forms, and then suddenly a new version comes out that has less detail than any version seen before due to crushed blacks/blown-out whites.

In that scenario, I honestly don't understand how the version with less detail can be defended in any way, even without an objective reference to compare it to.

Am I mistaken? In a scene filmed 'day for night', how bright and how detailed should it be?

What you say has merit, however, I just don't think it's that simple even-though I believe many (on here) think it is. Which is the problem I'm bringing up. 

And you could say the example I noted is a corner-case. Yes, it is, but it's an extreme to show what is written below is mis-guided.

Erik Pancakes said:

In the absence of a definitive "this is how it's definitely supposed to look" source to compare it to, I would think the source that provides the most detail would be preferable. In that case, wouldn't a release that crushes blacks and/or blows out whites to the point of losing detail in those areas be undesirable?

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skoal said:

... I see lots of posts here and else where saying this version is bad because of black-crush or white-blow-outs, and that makes no sense.

 It's simple math ..

           CRUSH or BLOWOUT equals DAMAGE

.. and this is why:

In this shot from 2001: A Space Odyssey, you can see that the full spectrum is well within the limits of displayable area -- from above 0 (absolute black) to under 255 (absolute white). Within this range, we can manipulate it without damaging the makeup of the spectrum.

Above, I've moved the Low from it's default of 0 to 12 for absolute black and the High from it's default of 255 to 228 for absolute white. The before (left) and after (right) displays show that this increases the contrast of the original picture. The graph's red-shaded "flat" area indicates where are the absolute black and absolute white areas.

Notice that under the Low and High settings are % values of 0.000. That means 0% of the picture's spectrum is in those flat absolute areas. That means no picture damage has occurred. And that means no matter how we manipulate, as long as we don't cross into those absolute areas, the spectrum can be returned to it's original state. All the picture's detail information is still available for our de-manipulation (if we choose to do so).

However:

Above, I've forced (whether accidentally or deliberately) parts of the spectrum into those flat absolute areas. The after view looks to have more contrast than the previous settings (which may have been what was wanted), but otherwise the picture still seems to be okay. Only it isn't.

Notice that, with the newer Low and High settings, crush and blowout have increased to 5% of the picture, each. The graph shows that the varied detail of those areas of the spectrum have been flatten into the absolute areas. The picture has been damaged and there is no way to undo it -- all the original detail information has been lost.

So, what does all this really mean? It's the same as dripping black or white paint onto dark or light areas of the picture -- no detail, just a solid blob of maximum darkness or maximum lightness. Below, the crush and blowout damage is hi-lited by inverting the damage areas to prove it's really there, even if it's normally hard to see:

TOP - improperly adjusted picture caused crush & blowout damage
MIDDLE - crush damage hi-lited
BOTTOM - blowout damage hi-lited
[note: RGB hi-lites can mix to produce R-G, R-B, G-B, and R-G-B colors]

Likely not - but the kind of crushing and blowout on modern transfers is comparable to "loudness war" re-EQ'ing of older music on modern re-releases. The original theatrical prints didn't have the full range of negative detail either, but the way it's handled now wipes out detail that WOULD have shown up on theatrical prints.

The Star Wars films are another example I can think of. The modern releases crush the blacks to the point that many of the stars in the space shots are just gone. But some of us have seen original 35mm theatrical prints, and even though they have higher contrast and less detail than the negatives would, the space backgrounds are loaded with stars.